title: Alternative splicing of the trout Pax5 gene and identification of novel B cell populations using Pax5 signatures.
abstract: Pax5 is an alternatively spliced transcription factor that regulates B cell development and activation. The function of specific Pax5 isoforms is unknown. Here we report the existence of seven alternatively spliced isoforms of Pax5 in the rainbow trout. We hypothesized that B cells differentially express specific Pax5 isoforms as a means of modulating Pax5 activity during cell maturation. Flow cytometric analyses using Pax5-specific antibodies recognizing the paired domain, a central (exon 6-encoding) domain, or the C-terminus, revealed the existence of distinct Pax5-expressing cell populations in trout immune tissues. Additionally, using the transcription factor EBF, we show that Pax5 isoforms lacking a paired domain are already expressed at the earliest stages of trout (B) lymphopoiesis, and unexpectedly, that minor populations of such cells reside in blood and spleen. These data support use of differentially expressed Pax5 isoforms to identify novel B cell subsets in the form of Pax5 tissue signatures, and as such, provides new biomarkers for malignancy, infectious disease, and disease resistance in trout and humans.
authors.affiliation: Department of Biology, The College of William and Mary, Williamsburg, VA 23185-8795, USA.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: MacMurray
authors.forename: Maggie
authors.initials: M
authors.lastname: Barr
authors.forename: Amber
authors.initials: A
authors.lastname: Bruce
authors.forename: Lidia
authors.initials: L
authors.lastname: Epp
authors.forename: Patty
authors.initials: P
authors.lastname: Zwollo
mesh_terms: D017398:Alternative Splicing; D000818:Animals; D016175:B-Lymphocyte Subsets / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D001402:B-Lymphocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D015153:Blotting, Western; D002478:Cells, Cultured; D029941:Fish Proteins / Q000235:genetics* / Q000378:metabolism; D005434:Flow Cytometry; D020869:Gene Expression Profiling; D007668:Kidney / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D017686:Oncorhynchus mykiss / Q000235:genetics* / Q000378:metabolism; D051757:PAX5 Transcription Factor / Q000235:genetics* / Q000378:metabolism; D054448:Precursor Cells, B-Lymphoid / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D029941:Fish Proteins; D008070:Lipopolysaccharides; D051757:PAX5 Transcription Factor; D020033:Protein Isoforms
keywords: 5-ethynyl-2′-deoxyuridine; Alternative splicing; B cell development; EBF; EdU; HCmu; IgM; PBL; Pax5; RAG1; SPL; Teleost; early B cell factor; immunoglobulin M; immunoglobulin heavy chain mu; peripheral blood lymphocyte; recombinase-activated gene; spleen